This invention, in general, relates to helicopters. In a more specific aspect the invention pertains to helicopter rail rotors.
It is known that in order to compensate for the torque component generated by the main rotor of a helicopter, the helicopter engine turns a tail rotor while it is turning the main rotor.
Tail rotors, while essential components, are nevertheless disadvantageous. They take power from the engine, introduce a drag force which must be overcome by the main rotor, add the weight of a power take-off, gear box, and a tail rotor drive shaft, and increase rotor noise. Apart from the reduction in size achievable by the fenestron tail rotor, the disadvantages of tail rotors remain. The weight and maintenance problems associated with a tail rotor drive mechanism have not been overcome. In addition to parasitic power consumption, there are usually over one thousand parts in a typical tail rotor gear train. Since the engine is as close as possible to the main rotor, the complexity, number of parts, weight and efficiency of the remote tail rotor have gone unchanged. By the practice of this invention, those parts, and hence their added weights, have been eliminated. And even more important, the tail rotor of this invention does not derive its power from the helicopter engine.